fs/nfsd/nfssvc.c

   1 /*
   2  * linux/fs/nfsd/nfssvc.c
   3  *
   4  * Central processing for nfsd.
   5  *
   6  * Authors:     Olaf Kirch (okir@monad.swb.de)
   7  *
   8  * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
   9  */
  10
  11 #include <linux/module.h>
  12
  13 #include <linux/time.h>
  14 #include <linux/errno.h>
  15 #include <linux/nfs.h>
  16 #include <linux/in.h>
  17 #include <linux/uio.h>
  18 #include <linux/unistd.h>
  19 #include <linux/slab.h>
  20 #include <linux/smp.h>
  21 #include <linux/smp_lock.h>
  22 #include <linux/fs_struct.h>
  23
  24 #include <linux/sunrpc/types.h>
  25 #include <linux/sunrpc/stats.h>
  26 #include <linux/sunrpc/svc.h>
  27 #include <linux/sunrpc/svcsock.h>
  28 #include <linux/sunrpc/cache.h>
  29 #include <linux/nfsd/nfsd.h>
  30 #include <linux/nfsd/stats.h>
  31 #include <linux/nfsd/cache.h>
  32 #include <linux/nfsd/syscall.h>
  33 #include <linux/lockd/bind.h>
  34 #include <linux/nfsacl.h>
  35
  36 #define NFSDDBG_FACILITY        NFSDDBG_SVC
  37
  38 /* these signals will be delivered to an nfsd thread
  39  * when handling a request
  40  */
  41 #define ALLOWED_SIGS    (sigmask(SIGKILL))
  42 /* these signals will be delivered to an nfsd thread
  43  * when not handling a request. i.e. when waiting
  44  */
  45 #define SHUTDOWN_SIGS   (sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT))
  46 /* if the last thread dies with SIGHUP, then the exports table is
  47  * left unchanged ( like 2.4-{0-9} ).  Any other signal will clear
  48  * the exports table (like 2.2).
  49  */
  50 #define SIG_NOCLEAN     SIGHUP
  51
  52 extern struct svc_program       nfsd_program;
  53 static void                     nfsd(struct svc_rqst *rqstp);
  54 struct timeval                  nfssvc_boot;
  55        struct svc_serv          *nfsd_serv;
  56 static atomic_t                 nfsd_busy;
  57 static unsigned long            nfsd_last_call;
  58 static DEFINE_SPINLOCK(nfsd_call_lock);
  59
  60 struct nfsd_list {
  61         struct list_head        list;
  62         struct task_struct      *task;
  63 };
  64 static struct list_head nfsd_list = LIST_HEAD_INIT(nfsd_list);
  65
  66 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
  67 static struct svc_stat  nfsd_acl_svcstats;
  68 static struct svc_version *     nfsd_acl_version[] = {
  69         [2] = &nfsd_acl_version2,
  70         [3] = &nfsd_acl_version3,
  71 };
  72
  73 #define NFSD_ACL_MINVERS            2
  74 #define NFSD_ACL_NRVERS         ARRAY_SIZE(nfsd_acl_version)
  75 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
  76
  77 static struct svc_program       nfsd_acl_program = {
  78         .pg_prog                = NFS_ACL_PROGRAM,
  79         .pg_nvers               = NFSD_ACL_NRVERS,
  80         .pg_vers                = nfsd_acl_versions,
  81         .pg_name                = "nfsd",
  82         .pg_class               = "nfsd",
  83         .pg_stats               = &nfsd_acl_svcstats,
  84         .pg_authenticate        = &svc_set_client,
  85 };
  86
  87 static struct svc_stat  nfsd_acl_svcstats = {
  88         .program        = &nfsd_acl_program,
  89 };
  90 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
  91
  92 static struct svc_version *     nfsd_version[] = {
  93         [2] = &nfsd_version2,
  94 #if defined(CONFIG_NFSD_V3)
  95         [3] = &nfsd_version3,
  96 #endif
  97 #if defined(CONFIG_NFSD_V4)
  98         [4] = &nfsd_version4,
  99 #endif
 100 };
 101
 102 #define NFSD_MINVERS            2
 103 #define NFSD_NRVERS             ARRAY_SIZE(nfsd_version)
 104 static struct svc_version *nfsd_versions[NFSD_NRVERS];
 105
 106 struct svc_program              nfsd_program = {
 107 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 108         .pg_next                = &nfsd_acl_program,
 109 #endif
 110         .pg_prog                = NFS_PROGRAM,          /* program number */
 111         .pg_nvers               = NFSD_NRVERS,          /* nr of entries in nfsd_version */
 112         .pg_vers                = nfsd_versions,        /* version table */
 113         .pg_name                = "nfsd",               /* program name */
 114         .pg_class               = "nfsd",               /* authentication class */
 115         .pg_stats               = &nfsd_svcstats,       /* version table */
 116         .pg_authenticate        = &svc_set_client,      /* export authentication */
 117
 118 };
 119
 120 /*
 121  * Maximum number of nfsd processes
 122  */
 123 #define NFSD_MAXSERVS           8192
 124
 125 int nfsd_nrthreads(void)
 126 {
 127         if (nfsd_serv == NULL)
 128                 return 0;
 129         else
 130                 return nfsd_serv->sv_nrthreads;
 131 }
 132
 133 int
 134 nfsd_svc(unsigned short port, int nrservs)
 135 {
 136         int     error;
 137         int     none_left, found_one, i;
 138         struct list_head *victim;
 139
 140         lock_kernel();
 141         dprintk("nfsd: creating service: vers 0x%x\n",
 142                 nfsd_versbits);
 143         error = -EINVAL;
 144         if (nrservs <= 0)
 145                 nrservs = 0;
 146         if (nrservs > NFSD_MAXSERVS)
 147                 nrservs = NFSD_MAXSERVS;
 148
 149         /* Readahead param cache - will no-op if it already exists */
 150         error = nfsd_racache_init(2*nrservs);
 151         if (error<0)
 152                 goto out;
 153         error = nfs4_state_start();
 154         if (error<0)
 155                 goto out;
 156         if (!nfsd_serv) {
 157                 /*
 158                  * Use the nfsd_ctlbits to define which
 159                  * versions that will be advertised.
 160                  * If nfsd_ctlbits doesn't list any version,
 161                  * export them all.
 162                  */
 163                 found_one = 0;
 164
 165                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
 166                         if (NFSCTL_VERISSET(nfsd_versbits, i)) {
 167                                 nfsd_program.pg_vers[i] = nfsd_version[i];
 168                                 found_one = 1;
 169                         } else
 170                                 nfsd_program.pg_vers[i] = NULL;
 171                 }
 172
 173                 if (!found_one) {
 174                         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
 175                                 nfsd_program.pg_vers[i] = nfsd_version[i];
 176                 }
 177
 178
 179 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 180                 found_one = 0;
 181
 182                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) {
 183                         if (NFSCTL_VERISSET(nfsd_versbits, i)) {
 184                                 nfsd_acl_program.pg_vers[i] =
 185                                         nfsd_acl_version[i];
 186                                 found_one = 1;
 187                         } else
 188                                 nfsd_acl_program.pg_vers[i] = NULL;
 189                 }
 190
 191                 if (!found_one) {
 192                         for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
 193                                 nfsd_acl_program.pg_vers[i] =
 194                                         nfsd_acl_version[i];
 195                 }
 196 #endif
 197
 198                 atomic_set(&nfsd_busy, 0);
 199                 error = -ENOMEM;
 200                 nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE);
 201                 if (nfsd_serv == NULL)
 202                         goto out;
 203                 error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
 204                 if (error < 0)
 205                         goto failure;
 206
 207 #ifdef CONFIG_NFSD_TCP
 208                 error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);
 209                 if (error < 0)
 210                         goto failure;
 211 #endif
 212                 do_gettimeofday(&nfssvc_boot);          /* record boot time */
 213         } else
 214                 nfsd_serv->sv_nrthreads++;
 215         nrservs -= (nfsd_serv->sv_nrthreads-1);
 216         while (nrservs > 0) {
 217                 nrservs--;
 218                 __module_get(THIS_MODULE);
 219                 error = svc_create_thread(nfsd, nfsd_serv);
 220                 if (error < 0) {
 221                         module_put(THIS_MODULE);
 222                         break;
 223                 }
 224         }
 225         victim = nfsd_list.next;
 226         while (nrservs < 0 && victim != &nfsd_list) {
 227                 struct nfsd_list *nl =
 228                         list_entry(victim,struct nfsd_list, list);
 229                 victim = victim->next;
 230                 send_sig(SIG_NOCLEAN, nl->task, 1);
 231                 nrservs++;
 232         }
 233  failure:
 234         none_left = (nfsd_serv->sv_nrthreads == 1);
 235         svc_destroy(nfsd_serv);         /* Release server */
 236         if (none_left) {
 237                 nfsd_serv = NULL;
 238                 nfsd_racache_shutdown();
 239                 nfs4_state_shutdown();
 240         }
 241  out:
 242         unlock_kernel();
 243         return error;
 244 }
 245
 246 static inline void
 247 update_thread_usage(int busy_threads)
 248 {
 249         unsigned long prev_call;
 250         unsigned long diff;
 251         int decile;
 252
 253         spin_lock(&nfsd_call_lock);
 254         prev_call = nfsd_last_call;
 255         nfsd_last_call = jiffies;
 256         decile = busy_threads*10/nfsdstats.th_cnt;
 257         if (decile>0 && decile <= 10) {
 258                 diff = nfsd_last_call - prev_call;
 259                 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
 260                         nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
 261                 if (decile == 10)
 262                         nfsdstats.th_fullcnt++;
 263         }
 264         spin_unlock(&nfsd_call_lock);
 265 }
 266
 267 /*
 268  * This is the NFS server kernel thread
 269  */
 270 static void
 271 nfsd(struct svc_rqst *rqstp)
 272 {
 273         struct svc_serv *serv = rqstp->rq_server;
 274         struct fs_struct *fsp;
 275         int             err;
 276         struct nfsd_list me;
 277         sigset_t shutdown_mask, allowed_mask;
 278
 279         /* Lock module and set up kernel thread */
 280         lock_kernel();
 281         daemonize("nfsd");
 282
 283         /* After daemonize() this kernel thread shares current->fs
 284          * with the init process. We need to create files with a
 285          * umask of 0 instead of init's umask. */
 286         fsp = copy_fs_struct(current->fs);
 287         if (!fsp) {
 288                 printk("Unable to start nfsd thread: out of memory\n");
 289                 goto out;
 290         }
 291         exit_fs(current);
 292         current->fs = fsp;
 293         current->fs->umask = 0;
 294
 295         siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
 296         siginitsetinv(&allowed_mask, ALLOWED_SIGS);
 297
 298         nfsdstats.th_cnt++;
 299
 300         lockd_up();                             /* start lockd */
 301
 302         me.task = current;
 303         list_add(&me.list, &nfsd_list);
 304
 305         unlock_kernel();
 306
 307         /*
 308          * We want less throttling in balance_dirty_pages() so that nfs to
 309          * localhost doesn't cause nfsd to lock up due to all the client's
 310          * dirty pages.
 311          */
 312         current->flags |= PF_LESS_THROTTLE;
 313
 314         /*
 315          * The main request loop
 316          */
 317         for (;;) {
 318                 /* Block all but the shutdown signals */
 319                 sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);
 320
 321                 /*
 322                  * Find a socket with data available and call its
 323                  * recvfrom routine.
 324                  */
 325                 while ((err = svc_recv(serv, rqstp,
 326                                        60*60*HZ)) == -EAGAIN)
 327                         ;
 328                 if (err < 0)
 329                         break;
 330                 update_thread_usage(atomic_read(&nfsd_busy));
 331                 atomic_inc(&nfsd_busy);
 332
 333                 /* Lock the export hash tables for reading. */
 334                 exp_readlock();
 335
 336                 /* Process request with signals blocked.  */
 337                 sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
 338
 339                 svc_process(serv, rqstp);
 340
 341                 /* Unlock export hash tables */
 342                 exp_readunlock();
 343                 update_thread_usage(atomic_read(&nfsd_busy));
 344                 atomic_dec(&nfsd_busy);
 345         }
 346
 347         if (err != -EINTR) {
 348                 printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
 349         } else {
 350                 unsigned int    signo;
 351
 352                 for (signo = 1; signo <= _NSIG; signo++)
 353                         if (sigismember(&current->pending.signal, signo) &&
 354                             !sigismember(&current->blocked, signo))
 355                                 break;
 356                 err = signo;
 357         }
 358         /* Clear signals before calling lockd_down() and svc_exit_thread() */
 359         flush_signals(current);
 360
 361         lock_kernel();
 362
 363         /* Release lockd */
 364         lockd_down();
 365
 366         /* Check if this is last thread */
 367         if (serv->sv_nrthreads==1) {
 368
 369                 printk(KERN_WARNING "nfsd: last server has exited\n");
 370                 if (err != SIG_NOCLEAN) {
 371                         printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
 372                         nfsd_export_flush();
 373                 }
 374                 nfsd_serv = NULL;
 375                 nfsd_racache_shutdown();        /* release read-ahead cache */
 376                 nfs4_state_shutdown();
 377         }
 378         list_del(&me.list);
 379         nfsdstats.th_cnt --;
 380
 381 out:
 382         /* Release the thread */
 383         svc_exit_thread(rqstp);
 384
 385         /* Release module */
 386         unlock_kernel();
 387         module_put_and_exit(0);
 388 }
 389
 390 int
 391 nfsd_dispatch(struct svc_rqst *rqstp, u32 *statp)
 392 {
 393         struct svc_procedure    *proc;
 394         kxdrproc_t              xdr;
 395         u32                     nfserr;
 396         u32                     *nfserrp;
 397
 398         dprintk("nfsd_dispatch: vers %d proc %d\n",
 399                                 rqstp->rq_vers, rqstp->rq_proc);
 400         proc = rqstp->rq_procinfo;
 401
 402         /* Check whether we have this call in the cache. */
 403         switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
 404         case RC_INTR:
 405         case RC_DROPIT:
 406                 return 0;
 407         case RC_REPLY:
 408                 return 1;
 409         case RC_DOIT:;
 410                 /* do it */
 411         }
 412
 413         /* Decode arguments */
 414         xdr = proc->pc_decode;
 415         if (xdr && !xdr(rqstp, (u32*)rqstp->rq_arg.head[0].iov_base,
 416                         rqstp->rq_argp)) {
 417                 dprintk("nfsd: failed to decode arguments!\n");
 418                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 419                 *statp = rpc_garbage_args;
 420                 return 1;
 421         }
 422
 423         /* need to grab the location to store the status, as
 424          * nfsv4 does some encoding while processing
 425          */
 426         nfserrp = rqstp->rq_res.head[0].iov_base
 427                 + rqstp->rq_res.head[0].iov_len;
 428         rqstp->rq_res.head[0].iov_len += sizeof(u32);
 429
 430         /* Now call the procedure handler, and encode NFS status. */
 431         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 432         if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2)
 433                 nfserr = nfserr_dropit;
 434         if (nfserr == nfserr_dropit) {
 435                 dprintk("nfsd: Dropping request due to malloc failure!\n");
 436                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 437                 return 0;
 438         }
 439
 440         if (rqstp->rq_proc != 0)
 441                 *nfserrp++ = nfserr;
 442
 443         /* Encode result.
 444          * For NFSv2, additional info is never returned in case of an error.
 445          */
 446         if (!(nfserr && rqstp->rq_vers == 2)) {
 447                 xdr = proc->pc_encode;
 448                 if (xdr && !xdr(rqstp, nfserrp,
 449                                 rqstp->rq_resp)) {
 450                         /* Failed to encode result. Release cache entry */
 451                         dprintk("nfsd: failed to encode result!\n");
 452                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 453                         *statp = rpc_system_err;
 454                         return 1;
 455                 }
 456         }
 457
 458         /* Store reply in cache. */
 459         nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
 460         return 1;
 461 }